New members on bone marrow registries worldwide are needed to allow sufficient diversity in the donor pool to meet patient needs. We used the theory of planned behaviour belief-basis and surveyed students who had not donated blood previously (i.e. non-donors) (N = 150) about the behavioural, normative, and control beliefs informing their intentions to join the Australian Bone Marrow Donor Registry. Key beliefs predicting non-donors' intentions included: viewing bone marrow donation as an invasion of the body (β = -.35), normative support from parents (β = .40), anticipating pain/side effects from giving blood (β = -.27), and lack of knowledge about how to register (β = -.30). Few non-donors endorsed these beliefs, suggesting they are ideal targets for change in strategies encouraging bone marrow donor registration.